Local computers are able to gain access to large volumes of information by communicating over telephone lines with remote data bases. The remote data base has storage capabilities which far exceed that which would be feasible at most local computers and can serve as a central storehouse of information.
A data base that was developed by the Walsh, Greenwood Information Systems, Inc. and which is now maintained by Wang Financial Information Services Corporation is dedicated to information relating to the stock market and other financial institutions. It contains real time trade and quote information including over-the-counter, option, commodity, futures, and fixed income data, as well as news and institutional holdings. The data base allows a subscribing computer to have access to three general classes of service: broadcast, inquiry and monitoring.
The broadcast class is that in which information is simply broadcast continuously to the user. An example is the New York Stock Exchange ticker service in which all transactions which occur on the New York Stock Exchange are transmitted to all subscribers as those transactions occur. Other broadcast services include a news headlines service which scrolls through headlines received from the Dow Jones News Service and the Reuters News Service. Also, the full news items from the Dow Jones News Service and the Reuters New Service are transmitted to subscribers to allow for scrolling through the news items as they are released.
Subscribers to the data base are also able to make specific inquiries. For example, a subscriber may send a request for a quotation on any stock item and promptly receive the current information stored at the data base for that stock item. News items of interest may also be retrieved by making requests which include specific identifier symbols which identify the information of interest.
Finally, a subscriber may request that the remote data base monitor all of the information which enters the data base and transmit only that data which is of particular interest to the subscriber. Again, the subscriber transmits a request to the data base which includes identifier symbols.
The Walsh Greenwood Information Systems system was designed for communication with personal computers; hence for communications line address there has been exactly one user. Each personal computer could subscribe to a particular set of services and pay the appropriate fee for those services. Configuration and security were handled by the network host processor sending a message to each computer on each line to indicate which services the network would allow that computer to use. This provided adequate control to permit accurate billing and accounting.